Insect repellants are widely used throughout the United States and throughout the world. In some regions, the use of insect repellants is critical to avoiding or reducing the occurrence of disease carried by insects. For example the Centers for Disease Control (CDC) receives nearly 10,000 reports of Lyme disease (transmitted by deer ticks) and 1,000 reports of encephalitis (transmitted by mosquitoes) annually).
Currently, the most common insect repellent is N,N-diethyl-meta-toluamide (DEET). DEET was designed to be applicable to the skin of subjects, and is designed to repel rather than kill insects. Although in use for some time, concern has recently emerged about the potential toxicity of DEET to children. Recently the US Environmental Protection Agency (EPA) determined that it would no longer allow child safety claims on labels for DEET-containing products.
The United States EPA Facts: Methyl Nonyl Ketone (July 1995) describes methyl nonyl ketone as a dog and cat repellent/training aid and iris borer deterrent, but does not suggest its use as an insect repellent.
U.S. Pat. No. 2,283,471 to Swaine describes the use of compounds such as methyl nonyl ketone and methyl undecyl ketone as contact insecticides for aphids and similar piercing-sucking insects (all primitive plant-feeding insects) which require contact insecticides for their control, but does not suggest their use as insect repellents.
R. Linderman et al., Pesticide Biochemistry and Physiology 35, 291-299 (1989), describes the inhibition of insect juvenile hormone esterase by α,β-unsaturated and α-acetylenic trifluoromethyl ketones, but does not suggest the use thereof as insect repellents.
Accordingly, there remains a need for new ways to repel insects, particularly mosquitoes and ticks.